2 * linux/arch/arm/kernel/entry-common.S
4 * Copyright (C) 2000 Russell King
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
10 #include <linux/config.h>
12 #include <asm/unistd.h>
14 #include "entry-header.S"
19 * This is the fast syscall return path. We do as little as
20 * possible here, and this includes saving r0 back into the SVC
24 disable_irq @ disable interrupts
25 ldr r1, [tsk, #TI_FLAGS]
26 tst r1, #_TIF_WORK_MASK
29 @ fast_restore_user_regs
30 ldr r1, [sp, #S_OFF + S_PSR] @ get calling cpsr
31 ldr lr, [sp, #S_OFF + S_PC]! @ get pc
32 msr spsr_cxsf, r1 @ save in spsr_svc
33 ldmdb sp, {r1 - lr}^ @ get calling r1 - lr
35 add sp, sp, #S_FRAME_SIZE - S_PC
36 movs pc, lr @ return & move spsr_svc into cpsr
39 * Ok, we need to do extra processing, enter the slow path.
42 str r0, [sp, #S_R0+S_OFF]! @ returned r0
44 tst r1, #_TIF_NEED_RESCHED
46 tst r1, #_TIF_NOTIFY_RESUME | _TIF_SIGPENDING
49 mov r2, why @ 'syscall'
51 b ret_slow_syscall @ Check work again
56 * "slow" syscall return path. "why" tells us if this was a real syscall.
60 disable_irq @ disable interrupts
61 ldr r1, [tsk, #TI_FLAGS]
62 tst r1, #_TIF_WORK_MASK
65 @ slow_restore_user_regs
66 ldr r1, [sp, #S_PSR] @ get calling cpsr
67 ldr lr, [sp, #S_PC]! @ get pc
68 msr spsr_cxsf, r1 @ save in spsr_svc
69 ldmdb sp, {r0 - lr}^ @ get calling r1 - lr
71 add sp, sp, #S_FRAME_SIZE - S_PC
72 movs pc, lr @ return & move spsr_svc into cpsr
75 * This is how we return from a fork.
80 ldr r1, [tsk, #TI_FLAGS] @ check for syscall tracing
82 tst r1, #_TIF_SYSCALL_TRACE @ are we tracing syscalls?
85 mov r0, #1 @ trace exit [IP = 1]
92 /*=============================================================================
94 *-----------------------------------------------------------------------------
97 /* If we're optimising for StrongARM the resulting code won't
98 run on an ARM7 and we can save a couple of instructions.
100 #ifdef CONFIG_CPU_ARM710
101 #define A710(code...) code
103 ldmia sp, {r0 - lr}^ @ Get calling r0 - lr
105 add sp, sp, #S_FRAME_SIZE
108 #define A710(code...)
113 sub sp, sp, #S_FRAME_SIZE
114 stmia sp, {r0 - r12} @ Calling r0 - r12
116 stmdb r8, {sp, lr}^ @ Calling sp, lr
117 mrs r8, spsr @ called from non-FIQ mode, so ok.
118 str lr, [sp, #S_PC] @ Save calling PC
119 str r8, [sp, #S_PSR] @ Save CPSR
120 str r0, [sp, #S_OLD_R0] @ Save OLD_R0
124 * Get the system call number.
127 #if defined(CONFIG_OABI_COMPAT)
130 * If we have CONFIG_OABI_COMPAT then we need to look at the swi
131 * value to determine if it is an EABI or an old ABI call.
133 #ifdef CONFIG_ARM_THUMB
135 movne r10, #0 @ no thumb OABI emulation
136 ldreq r10, [lr, #-4] @ get SWI instruction
138 ldr r10, [lr, #-4] @ get SWI instruction
139 A710( and ip, r10, #0x0f000000 @ check for SWI )
140 A710( teq ip, #0x0f000000 )
141 A710( bne .Larm710bug )
144 #elif defined(CONFIG_AEABI)
147 * Pure EABI user space always put syscall number into scno (r7).
149 A710( ldr ip, [lr, #-4] @ get SWI instruction )
150 A710( and ip, ip, #0x0f000000 @ check for SWI )
151 A710( teq ip, #0x0f000000 )
152 A710( bne .Larm710bug )
154 #elif defined(CONFIG_ARM_THUMB)
156 /* Legacy ABI only, possibly thumb mode. */
157 tst r8, #PSR_T_BIT @ this is SPSR from save_user_regs
158 addne scno, r7, #__NR_SYSCALL_BASE @ put OS number in
159 ldreq scno, [lr, #-4]
163 /* Legacy ABI only. */
164 ldr scno, [lr, #-4] @ get SWI instruction
165 A710( and ip, scno, #0x0f000000 @ check for SWI )
166 A710( teq ip, #0x0f000000 )
167 A710( bne .Larm710bug )
171 #ifdef CONFIG_ALIGNMENT_TRAP
172 ldr ip, __cr_alignment
174 mcr p15, 0, ip, c1, c0 @ update control register
179 adr tbl, sys_call_table @ load syscall table pointer
180 ldr ip, [tsk, #TI_FLAGS] @ check for syscall tracing
182 #if defined(CONFIG_OABI_COMPAT)
184 * If the swi argument is zero, this is an EABI call and we do nothing.
186 * If this is an old ABI call, get the syscall number into scno and
187 * get the old ABI syscall table address.
189 bics r10, r10, #0xff000000
190 eorne scno, r10, #__NR_OABI_SYSCALL_BASE
191 ldrne tbl, =sys_oabi_call_table
192 #elif !defined(CONFIG_AEABI)
193 bic scno, scno, #0xff000000 @ mask off SWI op-code
194 eor scno, scno, #__NR_SYSCALL_BASE @ check OS number
197 stmdb sp!, {r4, r5} @ push fifth and sixth args
198 tst ip, #_TIF_SYSCALL_TRACE @ are we tracing syscalls?
201 cmp scno, #NR_syscalls @ check upper syscall limit
202 adr lr, ret_fast_syscall @ return address
203 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
206 2: mov why, #0 @ no longer a real syscall
207 cmp scno, #(__ARM_NR_BASE - __NR_SYSCALL_BASE)
208 eor r0, scno, #__NR_SYSCALL_BASE @ put OS number back
210 b sys_ni_syscall @ not private func
213 * This is the really slow path. We're going to be doing
214 * context switches, and waiting for our parent to respond.
219 mov r0, #0 @ trace entry [IP = 0]
222 adr lr, __sys_trace_return @ return address
223 mov scno, r0 @ syscall number (possibly new)
224 add r1, sp, #S_R0 + S_OFF @ pointer to regs
225 cmp scno, #NR_syscalls @ check upper syscall limit
226 ldmccia r1, {r0 - r3} @ have to reload r0 - r3
227 ldrcc pc, [tbl, scno, lsl #2] @ call sys_* routine
231 str r0, [sp, #S_R0 + S_OFF]! @ save returned r0
234 mov r0, #1 @ trace exit [IP = 1]
239 #ifdef CONFIG_ALIGNMENT_TRAP
240 .type __cr_alignment, #object
247 * This is the syscall table declaration for native ABI syscalls.
248 * With EABI a couple syscalls are obsolete and defined as sys_ni_syscall.
250 #define ABI(native, compat) native
252 #define OBSOLETE(syscall) sys_ni_syscall
254 #define OBSOLETE(syscall) syscall
257 .type sys_call_table, #object
258 ENTRY(sys_call_table)
263 /*============================================================================
264 * Special system call wrappers
266 @ r0 = syscall number
268 .type sys_syscall, #function
270 eor scno, r0, #__NR_OABI_SYSCALL_BASE
271 cmp scno, #__NR_syscall - __NR_SYSCALL_BASE
272 cmpne scno, #NR_syscalls @ check range
273 stmloia sp, {r5, r6} @ shuffle args
278 ldrlo pc, [tbl, scno, lsl #2]
298 sys_sigsuspend_wrapper:
302 sys_rt_sigsuspend_wrapper:
306 sys_sigreturn_wrapper:
310 sys_rt_sigreturn_wrapper:
314 sys_sigaltstack_wrapper:
315 ldr r2, [sp, #S_OFF + S_SP]
318 sys_statfs64_wrapper:
323 sys_fstatfs64_wrapper:
329 * Note: off_4k (r5) is always units of 4K. If we can't do the requested
330 * offset, we return EINVAL.
335 moveq r5, r5, lsr #PAGE_SHIFT - 12
345 #ifdef CONFIG_OABI_COMPAT
348 * These are syscalls with argument register differences
364 sys_oabi_ftruncate64:
376 * Let's declare a second syscall table for old ABI binaries
377 * using the compatibility syscall entries.
379 #define ABI(native, compat) compat
380 #define OBSOLETE(syscall) syscall
382 .type sys_oabi_call_table, #object
383 ENTRY(sys_oabi_call_table)